Appointment

Judgement

What it is

Complete system

What it does

Thunderbird's scheduling tool that lets others book time on your calendar through a shared booking page.

Adopt it when

You want a privacy-minded Calendly alternative, hosted by Thunderbird Pro or self-run.

Watch out

Tied to Thunderbird's paid Pro service plans, and still evolving.

Ready for

Usable

Runs as

Self-hosted server and cloud service

Built with

Python, Vue, TypeScript, PostgreSQL and Redis

How established

Established: started 4 years ago, latest release r-0954.

What the license allows

You can use it inside a product you sell; changes you make to its own files must be shared.

Judged on 2026-11-03 from the project's README and GitHub data. The license and age lines are worked out directly.

Built from

Follow it down: Appointment → CPython → GCC → LLVM project → runs on a microchip

How compilers were built, back to punched paper tape

Open-source alternatives to Appointment

1. 1
   Cal.diy calcom

   Scheduling infrastructure for absolutely everyone.

   Complete system Usable You want to self-host personal booking links without a Cal.com licence and can run Next.js with Postgres.

   ★ 50k MIT TypeScript Active, pushed today
2. 2
   Rallly lukevella

   Rallly is an open-source scheduling and collaboration tool designed to make organizing events and meetings easier.

   Complete system Production-ready You often coordinate meetings or events with people outside your organisation and want an ad-free Doodle replacement.

   ★ 5.3k AGPL-3.0 TypeScript Active, pushed today
3. 3
   Easyappointments alextselegidis

   :date: Easy!Appointments - Self Hosted Appointment Scheduler

   Complete system Production-ready A small service business wants online booking on its own PHP hosting without subscription fees.

   ★ 4.5k GPL-3.0 PHP Active, pushed today
4. 4
   TastyIgniter tastyigniter

   :fire: Powerful, yet easy to use, open-source online ordering, table reservation and management system for restaurants

   Complete system Production-ready A restaurant wants its own ordering site instead of paying marketplace commissions.

   ★ 3.8k MIT PHP Active, pushed 16 days ago
5. 5
   Alf.io alfio-event

   alf.io - The open source ticket reservation system for conferences, trade shows, workshops, meetups

   Complete system Production-ready You run paid events and want to avoid Eventbrite fees and keep attendee data yourself.

   ★ 1.6k GPL-3.0 Java Active, pushed yesterday
6. 6
   LibreBooking LibreBooking

   LibreBooking is an open-source resource scheduling solution. It provides a flexible, mobile-friendly, and extensible interface for organizations to manage resource reservations. The "develop" branch contains the latest code of the project.

   Complete system Production-ready An organisation needs staff or members to reserve shared rooms or equipment under rules.

   ★ 844 GPL-3.0 PHP Active, pushed yesterday
7. 7
   Tymeslot Tymeslot

   Open-source meeting scheduling platform built with Elixir/Phoenix LiveView. Self-host or use the managed cloud at tymeslot.app.

   Complete system Usable A European business wants self-hostable scheduling without gated features.

   ★ 288 AGPL-3.0 Elixir Active, pushed 3 days ago
8. 8
   Django Appointment adamspd

   A Django app for managing appointment scheduling with ease and flexibility.

   Building block Usable Your Django site needs appointment booking for a service business.

   ★ 282 Apache-2.0 Python Active, pushed 10 days ago

Commercial booking and appointment scheduling tools

1. 1
   Eventbrite Eventbrite, Inc.

   Eventbrite - Discover the Best Local Events & Things to Do

   Complete system Production-ready You run public events and want ticketing plus exposure to people browsing Eventbrite for things to do.

   2.1k readers a month Since 2006 Commercial
2. 2
   Calendly Calendly

   Calendly connects and simplifies all of the work around meetings, from scheduling, payments, and meeting prep to notetaking, contact management, and follow-up.

   Complete system Production-ready Sales, recruiting or consulting staff spend time on back-and-forth emails to book meetings.

   1k readers a month Since 2013 Commercial
3. 3
   OpenTable Booking Holdings

   American internet company

   Complete system Production-ready A restaurant in a market where diners book through OpenTable wants that reservation demand.

   1k readers a month Since 1998 Commercial
4. 4
   Cvent Cvent

   Cvent provides software to planners for event management, marketing and attendee engagement, and also helps hotels win business through our sourcing platforms.

   Complete system Production-ready A corporate events team runs many conferences and meetings a year and needs sourcing, registration and reporting together.

   551 readers a month Since 1999 Commercial
5. 5
   Microsoft Bookings Microsoft

   Scheduling tool by Microsoft

   Complete system Production-ready An organisation on Microsoft 365 wants basic customer or internal booking at no extra cost.

   197 readers a month Since 2016 Commercial
6. 6
   Acuity Scheduling Squarespace

   Acuity Scheduling is an appointment booking software and a scheduling app, offering scheduling automation and full customization. Start a free trial today!

   Complete system Production-ready A solo practitioner or small service business wants client self-booking with forms and payments.

   Commercial